Passage
There shall not enter into it any thing defiled or that worketh abomination or maketh a lie: but they that are written in the book of life of the Lamb.
Revelation 21:27 (DRB)
Nearby Context
Revelation 21:25 And the gates thereof shall not be shut by day: for there shall be no night there.
Revelation 21:26 And they shall bring the glory and honour of the nations into it.
Revelation 21:27 There shall not enter into it any thing defiled or that worketh abomination or maketh a lie: but they that are written in the book of life of the Lamb.
Study Lenses
The verse centers on "shall", "enter", "defiled", "worketh", "abomination", "maketh", "written", and "book". It is saying that the verse draws attention to "shall" and "enter", so its meaning should be read from those terms before moving to application.
The prior verse says "And they shall bring the glory and...", giving immediate footing for "shall" and "enter". In Revelation context, the local focus is Christ, faith, and discipleship.
A plain takeaway is to answer the verse's own emphasis on "shall" and "enter" with trust shaped by these words, not by a vague optimism outside the passage.